1. Field of the Invention
The present invention relates to an image capturing apparatus provided with a peaking function, a control method for the image capturing apparatus, and a storage medium.
2. Description of the Related Art
Conventionally, focus adjustment of a shooting subject for a movie film is carried out in a digital cine-camera mostly by a camera operator performing a manual focus (MF) operation. There is a business-use digital video camera for a TV station etc. as well as a household digital video camera that can perform not only auto focus (AF) operation but can switch from AF to an MF operation.
In order to facilitate the focus adjustment, at the time of adjusting focus, a function can be utilized that emphasizes a high-frequency component and generates a clear contour of an image to display the captured image in a view finder. This function is referred to as “peaking, contour correction, edge emphasis, enhancer etc.” By this technique, the contour information is extracted from the captured image. The contour information is added to an original image to emphasize the contour.
For example, Japanese Patent No. 4,474,641 discloses a “focus adjustment signal generating apparatus”. In this apparatus, a luminance signal is converted into an RGB signal, each of which is filtered out through a low pass filter (LPF) or a high pass filter (HPF) in a vertical or horizontal direction. Then, addition is performed on absolute values of either LPF or HPF filtering results to generate the RGB signal for the focus adjustment.
Further, Japanese Patent No. 4,245,019 discloses a “view finder, image capturing apparatus and display signal generating circuit”. In this circuit, a high-frequency component is detected from each of three primary colors of a video signal to extract the peaking signal. Then, weighting addition is performed on the peaking signal, which is added to the three primary colors of the video signal.
On the other hand, a size of an image sensor becomes larger and shooting may be carried out with a fast lens so that movie shooting is carried out with a shallow depth of field. Coupled with high resolution of a captured image, it has become difficult to adjust focus in the MF operation.
When the peaking function for focus assistance is to be employed, while an image sensor becomes more and more multiplied and their size grows, miniaturization and streamlining of an imaging apparatus are also required. In such a circumstance, a display device with a high resolution and a large screen such as a viewfinder capable of displaying a shooting resolution as it is, cannot be always employed, and visibility for confirming the focus is not sufficiently achieved.